Ultrasound (US) imaging has provided useful information about the interior characteristics of an object or subject under examination. An US imaging system has included a probe with a transducer array of transducer elements. The transducer elements are configured to transmit ultrasound signals that traverse an examination region and to receive echo signals produced in response to the signals interacting with structure in the examination region. The echo signals are optionally pre-processed and then routed from the probe to processing electronics. A two-dimensional (2D) array may have thousands of transducer elements. With such a configuration, a large number of signals would need to be routed off the probe to the processing electronics.
One approach to handling such a large number of signals is to integrate certain electronics (e.g., an analog to digital converter (ADC), a multiplexor, etc.) into the probe, which, for example, could reduce the number of signals read out from the probe from thousands of signals to hundreds of signals. However, with this approach, there would need to be thousands of interconnects between the electronics in the probe and the transducer array. Unfortunately, drilling thousands of holes and/or routing thousands of electrical connections between the limited space of the footprints of the transducer and the electronics can be challenging and costly.
Another approach has included integrating an interposer, which has been configured to reduce the number of signals from thousands to hundreds, between the electronics in the probe and the transducer array. In this instance, the electronics have been packaged on printed circuit boards (PCB's) that are attached to one or more sides of the interposer via solder joints, with the transducer array being attached to the opposing side of the interposer via solder joints or conductive adhesives. With this configuration, the number of signals that are read out from the electronics can be reduced, along with complexity and cost.
Unfortunately, adding an interposer between the transducer array and the electronics introduces additional material(s) and therefore acoustic impedance mismatch boundaries (e.g., interposer/transducer array and interposer/electronics) and/or may introduce air between the transducer array and the electronics, which may result in unintended acoustic reflections and thus degrade image quality. Furthermore, the heat applied to melt and flow the solder that joins the electrical contacts of the interposer and the transducer array may degrade the transducing properties of the transducer array.